1. Field of Invention
The present invention relates to an electrostatic discharge structure, and more particularly to an electrostatic guiding structure with metal oxide generated through anodic oxidation.
2. Related Art
Electronic apparatus is mostly in an environment of electrostatic discharge (ESD). An electric field formed by a charged object makes the nearby gas ionize, so as to generate the ESD. The electrostatic interference may damage electronic devices or circuits. Although other electronic devices in the danger of the ESD may not be immediately damaged, the quality of the electronic apparatus is reduced, and the service life of the electronic apparatus is thus shortened.
The voltage generated by the ESD is quite high. When a relative humidity in the environment is lower than 50%, the voltage of the electrostatic charge accumulated on human body may exceed 30,000 V. However, the voltage sustained by most of the electrostatic sensitive devices is mostly lower than 100 V, and some electronic devices may be damaged by a voltage of merely 10 V. Particularly for the electronic apparatus having microelectronic devices, the microelectronic devices are more sensitive to the ESD. The microelectronic devices are mostly formed by stacking extremely tiny structures such as insulating layer, conductive layer, and semi-conductive layer, so the instant ESD may damage the inner structures of the microelectronic devices. The microelectronic devices that may be easily damaged by the ESD include, for example, a processor, an application specific integrated circuit (ASICS), and memory devices such as a random access memory (RAM) and a read only memory (ROM).
In addition, the ESD also interferes with the operating environment. The energy delivered or emitted by the ESD may be misrecognized as the valid data by the operating system, which results in a temporary error on the data during the transmission process.
Under the demand of the relative rules of the static electricity, during the manufacturing process, the electronic apparatus and the relative components are usually grounded or electrically connected to a negative voltage to prevent the generation of the static electricity.
Recently, desktop computers, mobile computers, mobile phones, digital audio/video devices, and other consumer electronic apparatus increasingly become popular. Metal color has elegant visual effect, so the electronic apparatus mostly adopt the metallic case as the outer case. Although the ESD effect may be reduced as the metallic case is directly electrically connected to the ground or the negative voltage, when a use contacts with the outer case, the user usually feels an electric shock. This results from leakage current. The leakage current makes the user uncomfortable, and may hurt the human body when it is too high.